882 Head Intake Port cc
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
882 Head Intake Port cc
My dyno numbers this past weekend were a dissappointment. I suspect some trans slippage under full throttle may have contributed to the early peak/plateau but also am concerned over the flow characteristics of my rebuilt 882 heads. Peak torque and hp occured at 3800rpm and declined from there (even though we continued to rev right up to 5000rpm). Is that the max for this head? I heard that, although not the most durable nor the best flowing of heads, they weren't that bad! :mad
I've added a higher lift/duration cam to the combination along with flat top pistons, Edelbrock performer intake and dynomax super turbo mufflers and walker high flow cat. I would have expected peak number in the upper 4000's but no go. :rolleyes:
I've added a higher lift/duration cam to the combination along with flat top pistons, Edelbrock performer intake and dynomax super turbo mufflers and walker high flow cat. I would have expected peak number in the upper 4000's but no go. :rolleyes:
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (e3pres)
I think the numbers where something line 167hp and 257 ft lbs of torque at the rear wheels. By the time the car hit 5000rpm, it was pulling 140mph (sitting still on the dyno rollers!)
Assuming 20% parasitic loss in the drivetrain (both hp and torque) I am looking at about 209hp and 321 ft lbs of torque at the flywheel with accessories (a/c not on). I suppose a 20hp (190hp stock) and 41 ft lbs (280 ft lbs stock) increase isn't all that bad, I was hoping for more but that makes the fact evident that taken together, the net increase of adding cam, mufflers, filter and pistons is less than the anticipated individual increases/impact of each. :(
[Modified by TedH, 10:51 AM 8/29/2001]
[Modified by TedH, 10:54 AM 8/29/2001]
Assuming 20% parasitic loss in the drivetrain (both hp and torque) I am looking at about 209hp and 321 ft lbs of torque at the flywheel with accessories (a/c not on). I suppose a 20hp (190hp stock) and 41 ft lbs (280 ft lbs stock) increase isn't all that bad, I was hoping for more but that makes the fact evident that taken together, the net increase of adding cam, mufflers, filter and pistons is less than the anticipated individual increases/impact of each. :(
[Modified by TedH, 10:51 AM 8/29/2001]
[Modified by TedH, 10:54 AM 8/29/2001]
Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Re: 882 Head Intake Port cc (TedH)
TedH,
I am not sure where you heard that info about the 882's, but it is simply incorrect. The 882's flow pretty well, but the poor design and large shape of the combustion chambers creates **** poor burn characteristics. To put it simply the flame front has to far to travel to consume all the fuel (which is spread out over the entire combustion chamber. If you were to look at a set of Vortec heads with the fast burn chambers, you would see that the combustion chamber is smaller, but more importantly the clearance volume is concentrated around the center line of the cylinder. Your problem may be the poor head design or possibly something else.
What type of cam are you using? Are you running headers? Did you mill the heads and/or use thinner head gaskets?
With standard flat tops the 882's will only make about 8.5-8.7:1 CR. If you mill the heads about .030" and use a .015"-.020" head gasket that will put you in the 9.8-10:1 range. Or just scrape the heads and go with the Vortec heads for $500/set complete + new intake.
I am not sure where you heard that info about the 882's, but it is simply incorrect. The 882's flow pretty well, but the poor design and large shape of the combustion chambers creates **** poor burn characteristics. To put it simply the flame front has to far to travel to consume all the fuel (which is spread out over the entire combustion chamber. If you were to look at a set of Vortec heads with the fast burn chambers, you would see that the combustion chamber is smaller, but more importantly the clearance volume is concentrated around the center line of the cylinder. Your problem may be the poor head design or possibly something else.
What type of cam are you using? Are you running headers? Did you mill the heads and/or use thinner head gaskets?
With standard flat tops the 882's will only make about 8.5-8.7:1 CR. If you mill the heads about .030" and use a .015"-.020" head gasket that will put you in the 9.8-10:1 range. Or just scrape the heads and go with the Vortec heads for $500/set complete + new intake.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (mean8t)
The cam is a Crane Energizer: .454/.454 lift, 216/216 duration at .050" with a 110 degree (I think) lobe separation. Stock cast manifolds with EFE actuator (flap) just below the right hand exhaust manifold before the exhaust pipe. Single high-flow catalytic converter (2-1-2 exhaust). The heads may have been milled a little as they were fully rebuilt by a company out of Oakland, CA for Advance Auto. Stock FelPro head gaskets.
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: 882 Head Intake Port cc (TedH)
TedH: My setup is very close to yours, (see my signiture), and I suspect my numbers would be close as well. I've been wondering if I should have lars rebuild and recalibrate a rochester carb for me. (I current have the ECM controled carb, and would like to replace with a non-computer rochester with an electric choke)
I wonder if you are missing out on some potential performance gains due to carburator no longer exactly meeting the modified engine requirements???
Just a thought.
I wonder if you are missing out on some potential performance gains due to carburator no longer exactly meeting the modified engine requirements???
Just a thought.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (john's '81 mouse)
That's one area the tuner wants to address. He wants to dial in my advance (both initial and total and when total is 'all in') as well as adjusting the secondary metering rods. He says the 13.1:1 air/fuel ratio is way to lean under WOT (it started around 13.6 at lower rpms and got leaner as the rpm increased). He is also going to run it on the dyno before/during/after the changes to see what benefits he can yield. All for $175. Sounds like a bargain! :cheers:
I'm also in the process (started day after dyno run) of switching to the 700R4 and a fresh set of 3.55's out back. May also go with true duals to accomodate the 700R4. Am hoping my 'before' numbers improve with these changes alone... :D
[Modified by TedH, 4:09 PM 8/29/2001]
I'm also in the process (started day after dyno run) of switching to the 700R4 and a fresh set of 3.55's out back. May also go with true duals to accomodate the 700R4. Am hoping my 'before' numbers improve with these changes alone... :D
[Modified by TedH, 4:09 PM 8/29/2001]
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (TedH)
In reading an old Chevy High Performance magazine, the 882 head is listed as the head with the smallest intake port size (and lowest flow numbers):
Category 1 - Port Size under 180cc:
GM 882 - 151 cc
GM 441 - 155 cc
GM 462 - 156 cc
GM L98 - 163 cc
Edelbrock Performer - 166 cc
GM Vortec - 170 cc
World Prod S/R Torquer - 170 cc
Category 2 - Port size 180 to 199 cc:
Brodix -8 - 181 cc
Holley SysteMax - 186 cc
AFR 190 - 191 cc
Canfield - 195 cc
TFS - 195 cc
I'm going to target the TFS 195 cc heads in Category 2...
Anything in Category 3 and higher are for beefier engines than mine...
Category 1 - Port Size under 180cc:
GM 882 - 151 cc
GM 441 - 155 cc
GM 462 - 156 cc
GM L98 - 163 cc
Edelbrock Performer - 166 cc
GM Vortec - 170 cc
World Prod S/R Torquer - 170 cc
Category 2 - Port size 180 to 199 cc:
Brodix -8 - 181 cc
Holley SysteMax - 186 cc
AFR 190 - 191 cc
Canfield - 195 cc
TFS - 195 cc
I'm going to target the TFS 195 cc heads in Category 2...
Anything in Category 3 and higher are for beefier engines than mine...
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Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Re: 882 Head Intake Port cc (TedH)
Ganey is right, I would definately go to some good headers (ie dynomax, hedman, etc) in additin to your duals. That should yield a substantial improvement over what you have now. I would seriously consider going to a different head, like the Vortec, or GM makes a factory replacement LT-1 head. Which are both good heads and come fully setup for 350 hp (the Vortec actually can support 450hp, b/c of the raised runner design). After you go to free flowing exhaust and headers, I would consider going to a 1.6:1 rocker arm to boost your lift to about .484".
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (mean8t)
My thoughts:
Keep the exhaust manifolds but add true 2.5" duals; reusing my Dynomax Super Turbo mufflers (true duals setup for 75-79)
Add Trick Flow 195cc heads, hardened pushrods and Comp roller tip rockers
The 700R4 and better 3.55s will be in the car in three weeks. I'd like to go the heads/exhaust route shortly thereafter...
Keep the exhaust manifolds but add true 2.5" duals; reusing my Dynomax Super Turbo mufflers (true duals setup for 75-79)
Add Trick Flow 195cc heads, hardened pushrods and Comp roller tip rockers
The 700R4 and better 3.55s will be in the car in three weeks. I'd like to go the heads/exhaust route shortly thereafter...
Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Re: 882 Head Intake Port cc (TedH)
TedH,
My question is still why keep the exhaust manifolds? The are extremely restrictive, your gain by going to true duals will be muffled b/c the exhaust will first have to go through a restrictive manifold. Additionaly, the cost of the headers (dynomax blackjack headers are about 85 bucks) is so marginal especially compared to the cost of the heads. That brings me to my last point, which is don't waste your money on heads if you don't use headers. Any airflow gain would be negated due to the engines lack of ability to pump air out. The engine is an air pump, air comes in air must go out.
My question is still why keep the exhaust manifolds? The are extremely restrictive, your gain by going to true duals will be muffled b/c the exhaust will first have to go through a restrictive manifold. Additionaly, the cost of the headers (dynomax blackjack headers are about 85 bucks) is so marginal especially compared to the cost of the heads. That brings me to my last point, which is don't waste your money on heads if you don't use headers. Any airflow gain would be negated due to the engines lack of ability to pump air out. The engine is an air pump, air comes in air must go out.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (mean8t)
I'm exploring A.I.R. compatible headers. Hedman sells a set under part number 68301 that appears to accomodate the original emmissions connections. If they do, I'm going to get a price for a ceramic-coated version and place my order...
Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Re: 882 Head Intake Port cc (TedH)
TedH
That sounds like a good idea. If I remember correctly, from when I lived in Tampa, they don't look under the hood in Tampa, just the sniffer test. If so you can get a way without using the air pump. If not you could make a set of headers, buy a set of uncoated headers, drill out holes for the fittings, then braze the fittings onto the headers, and then send the headers to Jet Hot and have them coated if you want. But I don't think that you will have any problem without the air pump. You could test this theory by unhooking the system and then taking it to a shop that does emmissions pre testing and see if it passes. Just my $0.02
That sounds like a good idea. If I remember correctly, from when I lived in Tampa, they don't look under the hood in Tampa, just the sniffer test. If so you can get a way without using the air pump. If not you could make a set of headers, buy a set of uncoated headers, drill out holes for the fittings, then braze the fittings onto the headers, and then send the headers to Jet Hot and have them coated if you want. But I don't think that you will have any problem without the air pump. You could test this theory by unhooking the system and then taking it to a shop that does emmissions pre testing and see if it passes. Just my $0.02
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (mean8t)
I'd definitely be stashing the air pump, A.I.R. and other related components with manifolds away for the day when Tampa has inspections again. Gov. Jeb Bush repealed the inspections when elected in 2000...
Let's see now, the list (in addition to my current trans/diff replacement) is now:
Trick Flow 23 degree heads with 1.25" springs (do these accomodate Comp Magnum Roller Rockers without modifications?), ARP head bolts and Fel Pro engine gasket kit
Hedman Ceramic-coat headers (A.I.R. not essential. Will remove and save with air pump, manifolds, and 2-1-2 cat converter exhaust for rainy day). So much for looking 'original' under the hood...
True dual exhaust system (reuse my Dynomax Super Turbo mufflers)
I'm thinking I need to buy a streetdamper harmonic balancer to tame all of those newly introduced high performance harmonics...
What kind of power would I be looking at with all of this added iron? Got the need to drop the hammah... :smash: :smash: :smash:
[Modified by TedH, 2:37 PM 8/30/2001]
Let's see now, the list (in addition to my current trans/diff replacement) is now:
Trick Flow 23 degree heads with 1.25" springs (do these accomodate Comp Magnum Roller Rockers without modifications?), ARP head bolts and Fel Pro engine gasket kit
Hedman Ceramic-coat headers (A.I.R. not essential. Will remove and save with air pump, manifolds, and 2-1-2 cat converter exhaust for rainy day). So much for looking 'original' under the hood...
True dual exhaust system (reuse my Dynomax Super Turbo mufflers)
I'm thinking I need to buy a streetdamper harmonic balancer to tame all of those newly introduced high performance harmonics...
What kind of power would I be looking at with all of this added iron? Got the need to drop the hammah... :smash: :smash: :smash:
[Modified by TedH, 2:37 PM 8/30/2001]
Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Re: 882 Head Intake Port cc (TedH)
The heads should accomodate the pro magnum roller rockers as long as you buy the ones to fit the studs that the heads have. To total everything up I would say somewhere in the 350hp at the flywheel. I am assuming that you are going with 1.6:1 rocker arms and 64 cc heads. I don't see why you wouldn't be getting into the mid 13's. Good luck.
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Re: 882 Head Intake Port cc (TedH)
That's one area the tuner wants to address. He wants to dial in my advance (both initial and total and when total is 'all in') as well as adjusting the secondary metering rods. He says the 13.1:1 air/fuel ratio is way to lean under WOT (it started around 13.6 at lower rpms and got leaner as the rpm increased). He is also going to run it on the dyno before/during/after the changes to see what benefits he can yield. All for $175. Sounds like a bargain! :cheers:
I'm also in the process (started day after dyno run) of switching to the 700R4 and a fresh set of 3.55's out back. May also go with true duals to accomodate the 700R4. Am hoping my 'before' numbers improve with these changes alone... :D
Am I a Dumass here or is a air/fuel ratio of 13.1:1 richer than a 13.6:1 ratio? I was lead to believe, that on a stock vehicle, you were shooting for 14:1 air/fuel ratio. (14 parts air per 1 part fuel)
Anyone, please correct me if I am wrong.
[Modified by TedH, 4:09 PM 8/29/2001]
I'm also in the process (started day after dyno run) of switching to the 700R4 and a fresh set of 3.55's out back. May also go with true duals to accomodate the 700R4. Am hoping my 'before' numbers improve with these changes alone... :D
Am I a Dumass here or is a air/fuel ratio of 13.1:1 richer than a 13.6:1 ratio? I was lead to believe, that on a stock vehicle, you were shooting for 14:1 air/fuel ratio. (14 parts air per 1 part fuel)
Anyone, please correct me if I am wrong.
[Modified by TedH, 4:09 PM 8/29/2001]
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: 882 Head Intake Port cc (glen242)
I'm only repeating what the tuner told me. Running too lean at 13.1:1. It definitely needs adjusting regardless...
How do you like the Trick Flows and what lessons did you learn when installing them? (thamilto@us.ibm.com)
[Modified by TedH, 7:27 AM 8/31/2001]
How do you like the Trick Flows and what lessons did you learn when installing them? (thamilto@us.ibm.com)
[Modified by TedH, 7:27 AM 8/31/2001]
